1. Field of the Invention
The present invention relates generally to a Partial Discharge (PD) counter for the diagnosis of a Gas Insulated Switchgear (GIS), which diagnoses a partial discharge using a partial discharge detection sensor in the GIS playing an important role among the power devices of a substation.
More particularly, the present invention relates to a partial discharge counter for the diagnosis of a GIS, which has a function of preventing malfunction from occurring due to external noise.
2. Description of the Related Art
A GIS system is configured such that SF6 gas is inserted into and sealed in a metal box and switches, such as a circuit breaker, a disconnector and a ground switch, and a three-phase (A, B and C phases) bus bar are fixedly installed in the metal box.
Such a GIS system has an advantage in that it is not easily influenced by changes in an external environment such as the strike of a thunderbolt because the GIS system is contained in the metal box, as well as structural advantages in that the GIS system is excellent in appearance, has a long lifespan owing to excellent insulating performance and is structurally optimized to enable the reduction of a substation.
However, a GIS system has disadvantages in that it is difficult to anticipate failures in advance and visibly detect such failures and in that once a failure occurs, it expands to become a large-scale failure.
Therefore, the development of a preventive diagnosis system for detecting failures in advance and taking preemptive action has been conducted, and a method of anticipating and measuring a partial discharge is determined to be the most influential method and has been widely used worldwide.
Meanwhile, a conventional online partial discharge diagnosis system is convenient in that it is possible to determine a partial discharge and continuously notify a substation equipment operator of the degree of the partial discharge, so that this system has been selectively applied to some important substations which require relatively accurate diagnosis. However, it is generally difficult to extensively apply the conventional system because the price thereof is so high that it amounts to several tens of % of the total cost of substation equipment.
In consideration of this disadvantage of the high price of the conventional online partial discharge diagnosis system, a portable GIS partial discharge diagnosis device has been used as an alternative conventional technology.
Although such a portable GIS partial discharge diagnosis device is not problematic from the standpoints of accuracy and the detection of a GIS partial discharge, there are no measures capable of processing a GIS partial discharge occurring at times other than the time of measurement because the monitoring of a partial discharge is only possible when a measurement is being conducted.